Heald frame rod comprising a displaceable heald damping element

ABSTRACT

A heald shaft ( 1 ) comprises at least one shaft rod ( 2 ) on which a damping element ( 12 ) is supported to be movable in the longitudinal direction of the heald. By virtue of movably supporting the damping element ( 12 ), an alignment of the healds ( 8 ) is improved and facilitated, and a desired damping effect is obtained during the entire motion course of the healds ( 8 ).

The invention relates to a shaft rod, particularly for a heald shaft ofa weaving machine, and includes the features of the preamble of claim 1.The invention further relates to a heald shaft provided with at leastone of such a shaft rod.

Heald shafts of weaving machines are, as a rule, formed of a rectangularframe whose long sides are constituted by so-called shaft rods. Eachshaft rod supports a shaft stave. Between the mutually parallel-arrangedshaft staves healds are disposed which, by means of their end eyelets,are attached to the shaft staves. Each heald has at least one threadeyelet through which a warp thread extends which is moved by the motionof the heald shaft for shed forming. The healds are held on the shaftstaves with a certain longitudinal play to enable them to freely alignthemselves in the lateral direction and to prevent them for being eithercompressed or extended. Such a play causes a continuous pounding orclattering of the healds against the shaft staves, creating a source ofnoise. Further, a stress on the healds is generated which may lead toheald breakage.

WO 01/48284 A1 discloses a heald shaft for a weaving machine. The shaftrods of the heald shaft each have a damping element on their sidesfacing the end eyelets of the healds. The damping element is arrangedwithin the play range of the end eyelet, so that the latter may abut thedamping element. Upon impact on the material having damping properties,lesser noise and mechanical stress on the heald are generated than incase of hard abutments.

The above principle is also realized according to U.S. Pat. No.3,895,655 and Swiss Patent 588582.

Rubber or the like is being considered as the damping material. In thecourse of the threading step, the healds stand with their end eyelets onthe lower damping element and remain suspended there by frictionalengagement. Such a circumstance renders the thread-in of the healds moredifficult. This is aggravated if a relatively small play is providedbetween the lower end eyelet and the damping element for the purpose oflimiting the back-and-forth pounding of the healds in their longitudinaldirection. If, on the other hand, a large play is provided for theoperation, the damping effect remains limited.

It is therefore an object of the invention to provide a shaft rod whichensures a low-noise operation. It is further an object of the inventionto provide a method of outfitting a heald shaft which includes at leastone shaft rod as described above and where the thread-in of the healdsmay be effected in a manner as uncomplicated as possible.

These objects are achieved with the shaft rod as defined in claim 1 andwith the method as defined in the method claim.

The shaft rod according to the invention comprises a damping elementwhich is arranged in the vicinity of the shaft stave and which istransversely movably supported on the shaft rod. Thus, the dampingelement is supported for displacement in the longitudinal direction ofthe healds. Such an arrangement results in a reduction of the wearbetween the shaft stave and the healds. The heald motion is damped veryeffectively. Further, the damping measure avoids heald breakages andresults in a noise reduction.

It is essential in the inventive shaft rod having a movable dampingelement that the healds be entrained, that is, pulled, by the shaftstaves, and that during the entire motion process, a damping element lieon the healds by virtue of gravity affecting the element or by virtue ofinertia. At the same time, the healds are freely movably supported andare damped only by the weight of the damping element. At the points ofreversal of the direction of motion of the heald shaft, the dampingelements assume, possibly briefly, a pushing function due to theirelasticity. At the reversal points the healds slightly penetrate intothe damping elements, so that the healds are gently, rather thanabruptly braked to thereafter continue their motion in the oppositedirection.

The loose support of the damping element on the shaft rod provides forthe possibility of facilitating the fitting of the heald shaft with thehealds. The damping element is not held fixedly on the heald shaft andthus may also move in the axial direction. This applies at least if, aspreferred, the damping element has a constant cross section along itslength. As a result, the heald shaft may be fitted with healds when thedamping element is still absent during such a step. First, the warpthreads may be threaded into the healds by a threading machine andthereafter the damping element is inserted into he heald shaft. Thecorresponding process steps are defined in the method claim.

The damping element is, for performing the process, preferablyreleasably connected to the heald shaft, that is, it is removably heldthereon. It may be removed from its seat, for example, by a slightelastic deformation. In such an embodiment no longitudinal mobility ofthe damping element is required. It is, however, also possible, to pullthe damping element longitudinally into its seat.

Further, the movable damping element provides for a reduction of theoscillations of the healds during operation of the weaving machine. Thismay lead to an improved appearance of the fabric. An oblique positioningof the healds as well as warp thread ruptures are prevented duringoperation.

In addition, the operating speed of the weaving machine and thus itsproductivity may be increased.

Further details of advantageous embodiments appear in the drawing, thedescription and the claims.

In the drawing, which illustrates examples of embodiments of theinvention,

FIG. 1 is a schematic front view of a heald shaft,

FIG. 2 is a fragmentary schematic front view of a shaft rod of the healdshaft of FIG. 1, shown with a heald,

FIGS. 3 and 4 are schematic, fragmentary cross-sectional illustrationsof a first embodiment of a shaft rod having a movable damping element,shown in different positions of the damping element,

FIGS. 5 and 6 are schematic, fragmentary cross-sectional illustrationsof a modified embodiment of a shaft rod having a movable damping elementshown in different positions,

FIG. 7 is a schematic, fragmentary cross-sectional view of a furthermodified embodiment of a shaft rod having a round, movably supporteddamping element,

FIG. 8 is a schematic, fragmentary cross-sectional view of an embodimentof a shaft rod having a form-fittingly held, movably supported dampingelement,

FIGS. 9 and 9 a are schematic cross-sectional views of a modifiedembodiment of a damping element,

FIG. 10 is a schematic cross-sectional view of a further, modifiedembodiment of a damping element, and

FIG. 11 is a schematic cross-sectional view of a further, modifiedembodiment of a damping element.

FIGS. 1 and 2 illustrate a heald shaft 1 forming part of a weavingmachine. The heald shaft is composed of an upper shaft rod 2, a lowershaft rod 3 extending parallel to the upper shaft rod 2 and end binders4, 5 connecting the shaft rods 2, 3 with one another. The shaft rods 2,3 and the end binders 4, 5 define a rectangular frame.

The shaft rod 2 and the shaft rod 3 hold a respective shaft stave 6, 7extending parallel to the respective shaft rod 2, 3. The shaft staves 6,7 are flat, steel profile members, while the shaft rods 2, 3 arepreferably extruded aluminum profile members. The heald shaft 1 hasmany, mutually parallel-arranged healds 8 which sit on the shaft staves6, 7 by means of their end eyelets 9, 11.

At least at one, but preferably at both shaft rods 2, 3, respectivedamping elements 12, 13 are arranged in the immediate vicinity of theend eyelets 9, 11. The damping elements 12, 13 are supported on theshaft rods 2, 3 for displacement in the working direction of the healdshaft 1 as indicated by the arrow 14 in FIG. 1. The working directioncorresponds to the longitudinal direction of the end binders 4, 5 andthe healds 8.

In the present embodiment the shaft rods 2, 3 are of identicalstructure. For this reason, in the description which follows, only theshaft rod 2 will be discussed to represent both the shaft rods 2 and 3.

The shaft rod 2 illustrated in FIGS. 3 and 4 has a box-profile shapedcarrier body 15 extending along the entire length of the shaft rod 2 andpreferably having a constant cross section. The carrier body 15 has, forexample, in its direction of motion, a narrow, upstanding rectangularprofile having two side walls 16, 17. A plate-like securing web 18extends away from the underside of the carrier body 15 as a linearcontinuation of the side wall 16. The securing web 18, for example,forms a single-piece component with the carrier body 15. On one of theflat sides of the securing web 18 a strip-like projection 19 is formedfor carrying the shaft stave 6. The latter extends parallel to thecarrier body 15 and is located underneath the lower narrow side thereof.Between the lower narrow side of the carrier body 15 and the shaft stave6 a buffer chamber 21 is formed into which extends the head 22 of theupper end eyelet 9 of the heald 8. The head is formed by a portion ofthe end eyelet 9, bent in a U shape and straddling the shaft stave 6. Inthe present embodiment the shaft stave 6 is, at its side oriented towardthe securing web 18, provided with a wide, groove-like longitudinalrecess 23 into which a holding lug 24 of the end eyelet 9 extends. Thewidth of the longitudinal recess 23 minus the width of the holding lug24 defines the longitudinal play of the heald 8. Such longitudinal play,however, may also be differently defined or limited.

In the buffer chamber 21 a damping element 12 is arranged which may be,for example, a cross-sectionally trapezoidal bar made of a dampingmaterial, such as plastic, a foam plastic, a plastic provided withhollow spaces, a synthetic fiber body or the like. The damping elementmay also be a bar or a strip made of a composite material (such as ametal-plastic composite, for example, a steel core having a plasticjacket), a jacketed foam body or a jacketed fiber body. The contour ofthe damping element conforms to the buffer chamber 21. At its sidefacing the planar securing web 18, the damping element has a planarsurface. The carrier body 15 has, externally at its underside, anoblique engagement surface 26. At that location the damping element 12has an engagement surface which too, is arranged obliquely, that is, atan obtuse angle to the securing web 18. The damping element 12 haslikewise a planar surface at its outer side which is oriented parallelto the side wall 17. At the side facing the head 22, the damping element12 may be provided with a strip-shaped planar surface or, if required,it may have a convexly or concavely bent surface. It is of importancethat the largest possible distance shown in FIG. 3 between the dampingelement 12 and the head 22 is less than the maximum play of the head 9on the shaft stave 6. Furthermore, the damping element 12 is movablysupported in such a manner that, as shown in FIG. 4, it may lie on theheads 22 of the healds 8 by virtue of its own weight and occasionally byits inertia, even if the healds 8 are at their maximum distance from thecarrier body 15. These conditions, namely the circumstance that, on theone hand, the distance between the damping element 12 and the head 22 ofthe heald 8 is less than the play of the heald 8 on the shaft staves 6,7 and, on the other hand, the damping element 12 lies on the heads 22 byvirtue of gravity, lead to a damping of the healds 8 during upward anddownward motion and at the points of reversal of the direction ofmotion. In case the distance between the damping element 12 and the head22 of the heald 8 is greater than the play of the heald 8 on the shaftstaves 6, 7, then the heald is, according to the invention, dampedduring upward and downward motion of the heald shaft 1 by virtue of theengagement of the damping element 12 with the healds.

In order to hold the damping element 12 securely in the buffer chamber21, the shaft rod 2 is, for example at its side wall 17, provided withsheet metal securing members 27 to 33 (FIG. 1) which may be glued to theoutside of the side wall 17. The sheet metal securing members 27 to 33extend beyond the engagement surface 26 by a distance which is greaterthan the maximum stroke H (FIG. 4) of the damping element 12. The strokeH is obtained from the distance measured from the upper edge of theshaft stave 6 to the engagement surface 26 minus the height of thedamping element 12 and the height of the head 22. The sheet metalsecuring members 27 to 33 thus straddle the damping element 12, even ifthe latter is situated in its lowest position (FIG. 4).

The heald shaft 1 as described above, operates as follows:

Before use, the heald shaft 1 has to be fitted with the healds 8. Forthis purpose, the latter are slid onto the shaft staves 6, 7 from theirends. This manipulation occurs in the absence of at least the lowerdamping element 12, but preferably in the absence of both dampingelements 12, 13. Thereafter the warp threads are threaded into thehealds 8, that is, into their thread eyelet by means of a threadinserting machine. The warp threads have the tendency to extend in alinearly taut manner. As a result, they cause alignment of the healds 8,which sit with a large play on the shaft staves 6, 7, until the healds 8have found their working position on the respective shaft staves 6, 7.At this point the damping elements 12, 13 may be inserted by slidingthem, for example, with a certain elastic deformation, over the sheetmetal securing members 27 to 33, into the buffer chamber 21 in whichthey will then loosely lie. In the alternative, the damping elements 12,13 may be axially drawn in. As a further alternative, it is feasible toreleasably connect, for example, by screws, the sheet metal securingmembers 27 to 33 with the carrier body 15. In such a case the sheetmetal securing members 27 to 33 may be removed for facilitating theinsertion of the damping elements 12, 13. In case of sufficientflexibility, the damping elements 12, 13 may also be introduced into thebuffer chamber 21 through the gaps between the sheet metal securingelements 27 to 33.

After completion of the outfitting of the heald shaft 1, the weavingmachine may start its normal operation, during which the heald shaft 1is reciprocated very rapidly and with very abrupt motions in thedirection of the arrow 14 (FIG. 1). The healds 8, moving together withthe heald shaft 1, have to be braked to a stop and then accelerated eachtime at the upper and lower reversal points of the heald shaft 1. Due togravity and the weight of the damping element 12, the upper dampingelement, designated at 12 in FIG. 1, lies directly on the associated endeyelets 9 of the healds 8. Thus, the damping element has a quieting,oscillation-absorbing and damping effect. At the points of reversal ofthe direction of motion of the heald shaft, the damping element 12, 13impacts on the engagement surface 26, whereby the motion of the dampingelement is limited. The healds 8 which follow the damping element 12, 13are then caught relatively softly by partially penetrating into the softdamping material and are thereafter again accelerated in the oppositedirection. During the braking process, the healds 8 push the dampingelement 12 or 13 in front of themselves and are damped thereby alreadyat that point. Then they impact with the damping element 12, forexample, on the engagement surface 26 and are braked there to a fullstop. Such a braking process which initiates the change in the directionof motion, proceeds with less oscillation and softer than in case of afixed support of the damping element 12, for example, at the engagementsurface 26. It is of importance in a shaft rod according to theinvention, provided with movable damping strips 12, 13, that the healds8 are entrained by the shaft staves 6, 7, that is, they are pulled, inwhich case at the points of reversal of the direction of motion thedamping elements 12, 13 assume, preferably for a short period, a pushingfunction due to their elasticity.

In FIGS. 5 and 6 the shaft rod 2 has a modified shaft stave 6 andlikewise, the healds 8 have modified end eyelets 9. The latter surroundthe shaft stave 6 in a C-shaped manner. The play of the healds 8 in thelongitudinal heald direction is obtained from the difference of theheight of the shaft stave 6 measured in the longitudinal heald direction(arrow 14) and the inner width of the end eyelet 9 measured in the samedirection. Such a play S is greater than the maximum distance A betweenthe damping element 12 and the head 22. The distance A is obtained asthe difference between the height of the buffer chamber 21 and theheight of the damping element 12. The height of the buffer chamber 21 isobtained from the distance measured from the engagement surface 26 tothe outer edge of the head 22 of the end eyelet 9, 11. As shown in FIG.6, the damping element 12 may freely move in the working direction(arrow 14) in the buffer chamber 21 and may arrive into engagement withthe engagement surface 26 as well as the head 22. During operation ofthe weaving machine, as the heald shaft 1 executes an oscillating motionin the direction of the arrow 14, the damping element and the healds 8perform jointly a reciprocating motion, while they are, to a largemeasure, in engagement with one another, resulting in theabove-described damping effect for this embodiment as well.

FIG. 7 illustrates a further modified embodiment of the shaft rod 2.This embodiment is based to a large measure on the embodiment of FIGS. 5and 6 and thus the previous description accordingly applies. The figuredescription of FIGS. 1 to 4 applies complementally.

In this instance, the damping element 12 has a circular cross sectionand again, is of a damping material. It is, for example, formed by aplastic bar, a rubber bar or the like. In the carrier body 15 theengagement surface 26 is formed which, in this embodiment, isconstituted by a rounded trough. The engagement surface 26, togetherwith a flat, wall-like rib 34 which extends parallel to the securing web18, forms a receiving chamber for the damping element 12. The receivingchamber is part of the buffer chamber 21. In this embodiment, similarlyto the previously described embodiments, a certain play is presentbetween the securing web 18 and the frontal securing elements (the sheetmetal securing elements 27 to 33) which are here replaced by the rib 34which extends uninterruptedly in the longitudinal direction of the shaftrod 2.

By virtue of the above arrangement, between the engagement surface 26and the damping element 12 an air cushion is enclosed which may developa certain buffering effect. The damping element 12 may freely move inthe buffer space 21 and thus it may engage the head 22 or, in thealternative, the engagement surface 26. In case the shaft rod 2 movesrapidly, the damping element 12 first lies on the head 22. Upon abruptbraking of the shaft rod 2, as it occurs during a change in thedirection of motion, the damping element 12 and the healds 8, with theirend eyelets 9, 11, penetrate into the buffer chamber 21, as a result ofwhich the air cushion 35 is displaced. The latter then must escape pastthe damping element 12; this has a damping and thus an impact-reducingeffect, particularly in case of very rapid braking steps.

It is further feasible to provide the rib 34, for purposes ofcontrolling the escaping air cushion 35 or for saving weight, withapertures or interruptions in the shape of groove-like or slot-likemilled-out portions.

FIG. 8 illustrates a further modified embodiment of the shaft rod 2. Theprevious description concerning the same reference numerals applies tothis embodiment. In this case, however, the rib 34 is, at its free end,slightly bent inward toward the securing web 18. The latter has, at acorresponding location, a rib-like projection 36 which bounds a slotwith the rib 34. The slot is open toward the shaft stave 6 and lies withthe latter preferably in the same plane. The slot, however, may beslightly offset, as shown.

The damping element 12 is in this instance a profile element having adamping cushion 37 which is joined by a web 38 passing through the slot.The web 38 extends perpendicularly from the damping cushion 37 into aninner chamber 39 surrounded, on the one hand, by the rear wall 18 and,on the other hand, by the rib 34. The inner chamber 39 is closed at thetop by the engagement surface 26 which is engaged by a bead-like headregion 41 formed at the free end of the web 38.

The damping element 12 has a play measured in the working direction(arrow 14). The range of play of the damping element 12 intersects—likein all the other previously described embodiments—the range of play ofthe end eyelet 9, that is, the damping element 12 and the head 22 may bein engagement with one another in any position inside the buffer chamber21. In this embodiment too, as in the embodiment according to FIG. 7, apneumatic damping effect may be obtained in addition to the mechanicaldamping.

FIG. 9 shows a damping element 12 in which a certain mobility is ensuredby means of a hollow chamber 42. This damping element 12 may findapplication in the shaft rod configurations of FIGS. 3, 4, 5, 6 andothers; therefore, the earlier description applies accordingly. In caseof a suitable flexibility of the damping element 12, the distancebetween the damping element 12 and the head 22 of the heald 8 may bereduced to zero. This, however, is not necessary. A reduction of thedistance between the damping element 12 and the head 22 of the heald 8to zero means that the damping strip 12 lies continuously on the heald 8and thus damps the latter during the upward and downward motions. Itfurther means that the damping element 12 is compressed at the points ofreversal of the direction of motion as the hollow chamber 42 (FIG. 9 a)undergoes deformation, and the originally approximately parallel sidewalls 44, 45 are pushed outward to assume an arcuate shape.

FIG. 10 illustrates a modified shape of a damping element 12 which ispressed by a spring force 43 in the direction of the heald 8. In thisembodiment too, as in case of the damping element 12 of FIGS. 9, 9 a, itis possible to reduce the distance between the damping element 12 andthe head 22 of the heald 8 to zero which, however, is not a requirementfor the inventive shaft rod. According to the invention, this dampingstrip too, lies on the head 22 by virtue of its own weight and inertiaand thus damps the heald 8 during its upward and downward motions. Incase the distance between the damping element 12 and the head 22 of theheald 8 is less than the play of the heald 8 on the shaft staves 6, 7,the heald 8 is damped at the reversal points of the direction of motionby the spring force 43. Such a spring force may be applied by variousspring means. The damping effect is increased if the damping element 12lies on the heald 8 with a bias exerted by the spring force. The dampingelement 12 according to FIG. 10 may find application in the shaft rodconfigurations of FIGS. 3, 4, 5, 6 and others. The springs 43 may beshort and thus may be supported with a play in their position of restfor rendering them active solely at the points of reversal.

FIG. 11 shows a damping element 12 with which different damping effectsmay be obtained dependent on its inserted position. This damping element12 too, is movably supported in the buffer chamber 21 and lies on thehead 22 of the heald 8 by virtue of gravity, so that the damping element12 damps the heald 8 during the upward and downward movements of theheald shaft 1. At the points of reversal of the direction of motion ofthe healds 8, the damping effect is, by using a damping element 12according to FIG. 11, dependent from the installed position of thedamping element 12. For obtaining different damping effects, therectangular damping element 12 includes damping regions 50 which, inthis embodiment, are formed on the outer surfaces 47 as recesses 46,such as troughs which may have different depths. The shape of the trough46 is adapted to the shape of the end of the head 22 of the heald 8 oris slightly larger. During the motion course, at the time when thedamping element 12 is in engagement with the engagement surface 26, thedepth D of the troughs 46 defines the moment at which the head 22 of theheald 8 tries to penetrate into the damping element 12. This is thephase during which a damping starts by virtue of the elasticity of thedamping strip 12. Such an elasticity is determined by the materialproperties of the damping strip 12 and/or by its shape. If, for example,the depth D of the trough 46, which is in contact with the engagementsurface 26, is zero, the damping is affected essentially only by thematerial properties of the damping element 12. If, on the contrary, thedepth D is very substantial, corresponding, for example, to one half ofthe height of the damping element 12, the damping is preponderantlydetermined by the shape of the damping element 12. The troughs of thedamping element 12 may have different depths, so that different dampingeffects may be obtained dependent on the installed position.

A heald shaft 1 comprises at least one shaft rod 2 on which a dampingelement 12 is supported to be movable in the longitudinal direction ofthe heald. By virtue of movably supporting the damping element 12, analignment of the healds 8 is improved and facilitated, and a desireddamping effect is obtained during the entire motion course of the healds8.

List of Reference Characters

-   1 heald shaft-   2, 3 shaft rod-   4, 5 end binders-   6, 7 shaft stave-   8 healds-   9, 11 end eyelets-   12, 13 damping element, heald damping element-   14 arrow (for the working direction)-   15 carrier body-   16, 17 side walls-   18 securing web-   19 projection-   21 buffer chamber-   22 head-   23 longitudinal recess-   24 holding lug-   26 engagement surface-   27 to 33 sheet metal securing members-   34 rib-   35 air cushion-   36 projection-   37 damping cushion-   38 web-   39 inner chamber-   41 head region-   42 hollow space-   43 spring element-   44, 45 side wall-   46 recess, trough-   47 outer surface-   A distance-   H stroke-   S play-   D depth

1. A shaft rod (2), particularly for a heald shaft (1) of a weavingmachine, including a carrier body (15) which carries a shaft stave (6)or on which a shaft stave (6) is formed, at least one heald dampingelement (12) supported on the carrier body (15), characterized in thatthe heald damping element (12) is supported to be movable transverselyto the carrier body (15).
 2. The shaft rod as defined in claim 1,characterized in that the heald damping element (12) is supported to bemovable in the longitudinal heald direction (14).
 3. The shaft rod asdefined in claim 1, characterized in that the shaft stave (6) isstructured such that the healds (8) are supported on the shaft stave (6)with a play (S) in the longitudinal heald direction (14).
 4. The shaftrod as defined in claim 1, characterized in that for movably supportingthe damping element (12), a support (27-33) is provided which allows adisplacement of the entire damping element (12) in a position near theshaft stave (6) and a counter motion of the damping element (12) in aposition remote from the shaft stave (6).
 5. The shaft rod as defined inclaim 1, characterized in that the damping element (12) is supported ina chamber into which it penetrates during its motion away from the shaftstave (6) while displacing air.
 6. The shaft rod as defined in claim 1,characterized in that the damping element (12) is longitudinallydisplaceably supported.
 7. The shaft rod as defined in claim 1,characterized in that the damping element (12) is frictionally held forassisting the damping.
 8. The shaft rod as defined in claim 1,characterized in that the damping element (12) is form-fittingly heldwith play.
 9. The shaft rod as defined in claim 1, characterized in thatthe damping element (12) is of a yielding material.
 10. The shaft rod asdefined in claim 1, characterized in that the damping element (12) has adeformable hollow space (42).
 11. The shaft rod as defined in claim 1,characterized in that the damping element (12) is displaceably supportedagainst a spring force (43).
 12. The shaft rod as defined in claim 1,characterized in that the damping element (12) has at least two outersurfaces (47) which have unlike shapes.
 13. The shaft rod as defined inclaim 1, characterized in that the damping element (12) has at least twodamping regions (50) which damp differently from one another.
 14. Aheald shaft having a shaft rod as defined according to one of claims 1to
 13. 15. A method of fitting a heald shaft with healds and/orthreading threads into the healds, in which the fitting step and/or thethreading step is performed on a heald shaft; the damping element fromat least one shaft rod of the heald shaft having been removed, and aftercompleting the fitting and/or the threading step, the damping element ismounted on the shaft rod.